Lactate clearance predicts mortality in sepsis patients during initial phase of resuscitation
Arterial lactate concentrations and lactate clearance are predictors of mortality in patients with sepsis during the initial phase of resuscitation, a new study has found.
Researchers collected serum samples from 100 septic shock patients (mean age, 63±11 years; 57 males) at baseline and after 6 hours of resuscitation. Samples were drawn from both arterial and venous lines. Demographic variables, information on acute and chronic health status, and sequential organ failure assessment (SOFA) scores, among others, were also included in the analysis.
The average serum arterial and venous lactate concentrations at baseline were 3.0±0.6 and 3.7±0.8 mg/dL, respectively. In both sets of samples, the serum lactate levels dropped significantly after 6 hours of resuscitation (arterial: mean difference, 0.86, 95 percent CI, 0.74–0.98; venous: mean difference, 0.98, 0.81–1.15).
Baseline arterial and venous lactate concentrations shared a direct, linear and significant correlation (R2, 0.587; p<0.001), which grew even stronger after 6 hours of resuscitation (R2, 0.887; p<0.00). However, venous samples consistently had higher lactate levels than the arterial counterparts.
Receiver operator characteristic curve analysis showed that baseline arterial lactate concentration (area under the curve [AUC], 0.85±0.05) was a stronger predictor of mortality in the ICU than venous levels (AUC, 0.74±0.06; p<0.001). The respective cutoff values were 3.2 and 4.0 mg/dL.
Lactate clearance, defined as the removal of both arterial (AUC, 0.89±0.04) and venous (AUC, 0.85±0.05) lactate after 6 hours of resuscitation, was an even better predictor of ICU mortality than baseline arterial lactate.